The objective of this research project is to gain new insights on the long-term impact of meditation on basic affective and attention functions and on the brain mechanisms that subserve these processes. This project will focus on two standard meditative states and will study these states in a population of highly trained Buddhist lamas and a population of non-practitioners. The first meditative practice develops attention stability. In the second practice, the subject voluntarily generates a state of compassion. This research seeks to make these mental states a focus of scientific study. It could provide original data on the neural processes by which meditation plays a beneficial role in emotion regulation. Furthermore, these data would provide novel evidence to the view that attention and affective processes are flexible skills that can be trained. This study involves the measurement of functional and dynamical brain activity during these meditative states with high-density electroencephalography (EEG, 128 channels) and functional magnetic resonance imaging (fMRI, 3T). The fMRI and EEG paradigms will be run sequentially but with similar tasks allowing their complementary information to be combined. The primary aims of this research are: a) to identify the neural circuitry and neural mechanisms involved in the generation and the maintenance of these meditative states, and b) to characterize the impact of these states on the brain response to aversive, pleasant or neutral auditory stimuli. These questions will be addressed: a) from the EEG data, by studying the role of neural synchrony at fastfrequencies (30-80Hz) in the neural processes underlying meditation and b) from the fMRI data, by studying the role of amygdala, insula and prefrontal cortex in the generation and maintenance of these meditative states.